International Journal of Research and Innovation in Applied Science (IJRIAS) |Volume VII, Issue X, October 2022|ISSN 2454-6194
Sotonye Dere-Biemgbo, Obemeata Emmanuel Oriakpono*
Department of Animal and Environmental Biology, University of Port Harcourt, Port Harcourt Rivers State, Nigeria.
*Corresponding author
Abstract: A river’s physical, chemical and biological states indicate the quality of the aquatic system. This study assessed the level of total hydrocarbon content (THC) and other water and sediment characteristics in the Koniju-toru River of Okrika – an estuary of the Bonny River – for three months. Surface water, sediment and fish samples were collected from three stations (upstream, midstream and downstream) for three months. Composite samples of each station were tested for pH, total dissolved solids (TDS) and dissolved oxygen (DO) in-situ using HANNA multi-parameter meter while conductivity, nitrate, sulphate, phosphate, chloride and biochemical oxygen demand (BOD) were determined in the laboratory. Spectrophotometry was used for the determination of hydrocarbon content in the samples. The hydrocarbon content in surface water, sediment and fish ranged from 0.05 -0.12 mg/L, 2.13 – 3.83 mg/kg and 0.24 – 0.35 mg/kg, respectively. Other results characterizing the surface water included; pH (6.62 – 6.73), temperature (26.10 – 26.53 ℃), TDS (8888.3 – 10972.3 mg/L), chloride (6697.6 – 7598.3 mg/L), sulphate (259.1 – 346.5 mg/L), nitrate (0.17 – 0.29 mg/L), phosphate (0.002 – 0.066mg/L), DO (4.10 – 4.86 mg/L) and BOD (2.02 – 2.22 mg/L). Parameters in sediment ranged as follows; pH (5.12 – 5.60), alkalinity (50.3 – 100.3 mg/kg), chloride (504.7 – 604.8 mg/kg), sulphate (125.2 – 183.6 mg/kg), nitrate (0.11 – 0.30 mg/kg) and Total Organic Matter (0.60 – 0.73 mg/kg). Statistical tests showed significant difference (p < 0.05) between stations for all parameters. The study concluded that the physicochemical characteristics of water and sediment were within regulatory limits of WHO and other national standards excluding TDS, chloride and sulphate. levels of THC in surface water, sediment and fish were low suggesting little or no impact of industrial waste which may not be unassociated with the fact that the refinery with the most impact on the community was under rehabilitation.
Keywords: Fish; hydrocarbon; water; sediment; upper bonny estuary
I. INTRODUCTION
Oil exploration/exploitation has been identified as a major pollution source of aquatic systems in the Niger Delta [1]. [2] lists some sources of oil spills including refinery effluents, sabotage and leakages from marine vessels. Oil contains a mixture of hydrocarbons including aromatic and aliphatic ([3], [4], [5]); therefore, estimating the total hydrocarbon content of water is an indicator of an oil-contaminated water body.